<style>
    html {
        font-family: sans-serif;
        font-size: 150%;
    }

    :is(section.is-styling, aside.is-styling, footer.is-styling) a {
        color: red;
    }

    :where(section.where-styling, aside.where-styling, footer.where-styling) a {
        color: orange;
    }

    footer.is-styling a,footer a {
        color: blue;
    }
</style>
<article>
    <h2>:is()-styled links</h2>
    <section id="is-section" class="is-styling">
        <p>
            Here is my main content. This
            <a href="https://mozilla.org">contains a link</a>.
        </p>
    </section>

    <aside class="is-styling">
        <p>
            Here is my aside content. This
            <a href="https://developer.mozilla.org">also contains a link</a>.
        </p>
    </aside>

    <footer class="is-styling">
        <p>
            This is my footer, also containing
            <a href="https://github.com/mdn">a link</a>.
        </p>
    </footer>
</article>

<article>
    <h2>:where()-styled links</h2>
    <section class="where-styling">
        <p>
            Here is my main content. This
            <a href="https://mozilla.org">contains a link</a>.
        </p>
    </section>

    <aside class="where-styling">
        <p>
            Here is my aside content. This
            <a href="https://developer.mozilla.org">also contains a link</a>.
        </p>
    </aside>

    <footer class="where-styling">
        <p>
            This is my footer, also containing
            <a href="https://github.com/mdn">a link</a>.
        </p>
    </footer>
</article>